Multiple input multiple output (MIMO) techniques are the most promising technologies for next-generation wireless systems to achieve improved channel reliability as well as high spectral efficiencies. In real MIMO downlink scenarios, the numbers of users are usually greater than that of transmit antennas at a base station and the base station is likely to provide a variety of services to different quality-of-service (QoS) users. Therefore, a multiuser scheduling algorithm for the real MIMO BC scenarios has to support a mixture of QoS users simultaneously by exploiting the performance gains of multiple antennas whilst maximizing the sum-rate capacity by selecting a user set for transmission according to performance criteria. The main topic of this thesis is the design of QoS-guaranteed multiuser schedulers for MIMO systems. This should provide different QoS services to different users whilst satisfying the system-level requirements such as fairness among users, minimum data rate and delay constraints as well as trying to maximize the sum-rate capacity of MIMO channels. For this, this thesis first investigates the performance of MIMO transceiver techniques in terms of error rates and the sum-rate capacity with practical considerations to select a practically appropriate MIMO precoding technique. Then a QoS-aware sequential multiuser selection algorithm is proposed, which selects a user set sequentially from each QoS group in order to satisfy QoS requirements by trading off the transmit antennas between different QoS groups. Using a temporally-correlated MIMO channel model validated by channel measurements, a statistical channel state information (SCSI)-assisted multiuser scheduling algorithm is also proposed, which can minimize the effect of the temporal correlation on the sum-rate capacity. Finally, new metrics are proposed to support fairness among users in terms of throughput or delay whilst maximising the sum-rate capacity. With these proposed algorithms, the objective of this thesis, to support a mixture of different QoS users simultaneously with fairness considerations whilst maximising the sum-rate capacity by exploiting the advantages of MIMO techniques with practical implementation in mind, can be achieved.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:653779 |
| Date | January 2007 |
| Creators | Lee, Seung-Hwan |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/15199 |
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